On 2017年10月23日 18:51, Nikolay Borisov wrote:
> btrfs_balance_delayed_items is the sole caller of btrfs_wq_run_delayed_node and
> already includes one of the checks whether the delayed inodes should be run. On
> the other hand btrfs_wq_run_delayed_node duplicates that check and performs an
> additional one for wq congestion.
>
> Let's remove the duplicate check and move the congestion one in
> btrfs_balance_delayed_items, leaving btrfs_wq_run_delayed_node to only care
> about setting up the wq run. No functional changes.
>
> Signed-off-by: Nikolay Borisov <nborisov@xxxxxxxx>
btrfs_workqueue_normal_congested() is moved to the caller and removed
duplicated atomic_read().
Unless delayed_root->items get modified in the period, it should be good.
But anyway, the original code has nothing to protect different
atomic_read(), so I don't think it will cause any new problem.
Reviewed-by: Qu Wenruo <wqu@xxxxxxxx>
Thanks,
Qu
> ---
> fs/btrfs/delayed-inode.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
>
> diff --git a/fs/btrfs/delayed-inode.c b/fs/btrfs/delayed-inode.c
> index 1bfdb90d7633..b7a0ec2c41e6 100644
> --- a/fs/btrfs/delayed-inode.c
> +++ b/fs/btrfs/delayed-inode.c
> @@ -1371,10 +1371,6 @@ static int btrfs_wq_run_delayed_node(struct btrfs_delayed_root *delayed_root,
> {
> struct btrfs_async_delayed_work *async_work;
>
> - if (atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND ||
> - btrfs_workqueue_normal_congested(fs_info->delayed_workers))
> - return 0;
> -
> async_work = kmalloc(sizeof(*async_work), GFP_NOFS);
> if (!async_work)
> return -ENOMEM;
> @@ -1410,7 +1406,8 @@ void btrfs_balance_delayed_items(struct btrfs_fs_info *fs_info)
> {
> struct btrfs_delayed_root *delayed_root = fs_info->delayed_root;
>
> - if (atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND)
> + if ((atomic_read(&delayed_root->items) < BTRFS_DELAYED_BACKGROUND) ||
> + btrfs_workqueue_normal_congested(fs_info->delayed_workers))
> return;
>
> if (atomic_read(&delayed_root->items) >= BTRFS_DELAYED_WRITEBACK) {
>
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